As a participating institution in the Primary Breast Cancer Therapy Group, we are contributing data from patients entered into the various group protocols. The present continuation seeks to place patients in the following protocols: (1) No. 6: A trial to compare the worth of segmental mastectomy with and without breast radiation with total mastectomy plus axillary dissection. All patients will undergo axillary dissection and those with histologically positive nodes will receive adjuvant chemotherapy. (2) No. 9: A trial to determine whether the antiestrogen Tamoxifen, when combined with chemotherapy, improves the results obtained with chemotherapy alone. (3) No. 10: A trial to compare the value of the immunopotentiator C. parvum combined with chemotherapy vs. chemotherapy alone. Our participation in these protocols will provide data from a sufficient number of patients to answer specific questions concerning the value of certain therapeutic modalities in the management of primary breast cancer. Moreover, our participation in these protocols will enhance the multidisciplinary approach of this institution in clinical trials.